Dynamical Model MJO Forecasts

The U.S. CLIVAR program instituted a MJO working group to develop diagnostics related to the MJO during 2006. A subgroup was organized to focus on MJO operational prediction and was tasked to develop a MJO forecast metric for comparison of dynamical models from operational global prediction systems. The activity is housed at CPC where the application, display, and evaluation of these MJO model forecasts is being done. During 2010, the group was reformulated as the WCRP/WWRP THORPEX YOTC Task Force. This website will see updates as additional models become available and verification statistics generated. The products at this site are to be considered EXPERIMENTAL at the current time.

A key for the label headings in the figure box is provided below. Click on the headings for additional information for specific model-related information such as the number of ensemble members, forecast duration and climatologies used.

Most plots are up to date as of 1PM ET on January 10. We anticipate good product reliability going forward, and we are grateful for your patience as we continue to work on making these products available in a timely manner.

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The methodology for the creation of the phase space plots above follows closely to that described in Wheeler and Hendon (2004) (hereafter WH2004). A notable difference between WH2004 and the procedure employed here is that the linear removal of the ENSO signal (related by the BMRC SST1 index) is not performed. After discussion among the MJOWG members, it was decided that this step was not necessary as the subsequent removal of the 120-day mean is sufficient to remove much of the interannual signal.

The table below summarizes the data requested by the MJOWG for the operational centers. For additional details regarding the data and methodology, see the document link below the table. This document includes background information and motivation for this activity along with directions for interested operational centers who wish to participate in this project.

Fields

OLR, u850, and u200 totals (anomaly fields optional)
Initial analysis, forecasts of all ensemble members, out to no more than 40 days

Resolution

2.5 in longitude (0, 2.5E. 5.0E, Daily averaged (00-24Z))

Update Frequency

Daily, or less for those systems run at a reduced frequency
Additional data during initial transfer (i.e., send analysis data for past 120 days)

The table below illustrates the current participation in the activity which is in varying stages for each of the participating centers. Various models are provided and include datastreams consisting of a varying number of ensemble members and forecast duration.

The US CLIVAR MJO Working Group plans to verify these forecasts in realtime using the bivariate correlation and root-mean-square error between the observed and forecasted RMM indices as described by Lin et al. (2008). See below for expressions and an example.
*** Please Note: Images below are examples at the current time. Realtime versions of equivalent or similar figures are expected in the future ***

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